Re: [PATCHv4 2/6] phy: improved lookup method

[Vivek Gautam]

Hi Heikki,


On Fri, Oct 17, 2014 at 8:09 PM, Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
> Removes the need for the phys to be aware of their users
> even when not using DT. The method is copied from clkdev.c.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> Tested-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
> ---
>  Documentation/phy.txt   |  66 ++++++++---------------
>  drivers/phy/phy-core.c  | 135 +++++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/phy/phy.h |  27 ++++++++++
>  3 files changed, 183 insertions(+), 45 deletions(-)
>
> diff --git a/Documentation/phy.txt b/Documentation/phy.txt
> index c6594af..8add515 100644
> --- a/Documentation/phy.txt
> +++ b/Documentation/phy.txt
> @@ -54,18 +54,14 @@ The PHY driver should create the PHY in order for other peripheral controllers
>  to make use of it. The PHY framework provides 2 APIs to create the PHY.
>
>  struct phy *phy_create(struct device *dev, struct device_node *node,
> -                      const struct phy_ops *ops,
> -                      struct phy_init_data *init_data);
> +                      const struct phy_ops *ops);
>  struct phy *devm_phy_create(struct device *dev, struct device_node *node,
> -                           const struct phy_ops *ops,
> -                           struct phy_init_data *init_data);
> +                           const struct phy_ops *ops);
>
>  The PHY drivers can use one of the above 2 APIs to create the PHY by passing
> -the device pointer, phy ops and init_data.
> +the device pointer and phy ops.
>  phy_ops is a set of function pointers for performing PHY operations such as
> -init, exit, power_on and power_off. *init_data* is mandatory to get a reference
> -to the PHY in the case of non-dt boot. See section *Board File Initialization*
> -on how init_data should be used.
> +init, exit, power_on and power_off.
>
>  Inorder to dereference the private data (in phy_ops), the phy provider driver
>  can use phy_set_drvdata() after creating the PHY and use phy_get_drvdata() in
> @@ -137,42 +133,24 @@ There are exported APIs like phy_pm_runtime_get, phy_pm_runtime_get_sync,
>  phy_pm_runtime_put, phy_pm_runtime_put_sync, phy_pm_runtime_allow and
>  phy_pm_runtime_forbid for performing PM operations.
>
> -8. Board File Initialization
> -
> -Certain board file initialization is necessary in order to get a reference
> -to the PHY in the case of non-dt boot.
> -Say we have a single device that implements 3 PHYs that of USB, SATA and PCIe,
> -then in the board file the following initialization should be done.
> -
> -struct phy_consumer consumers[] = {
> -       PHY_CONSUMER("dwc3.0", "usb"),
> -       PHY_CONSUMER("pcie.0", "pcie"),
> -       PHY_CONSUMER("sata.0", "sata"),
> -};
> -PHY_CONSUMER takes 2 parameters, first is the device name of the controller
> -(PHY consumer) and second is the port name.
> -
> -struct phy_init_data init_data = {
> -       .consumers = consumers,
> -       .num_consumers = ARRAY_SIZE(consumers),
> -};
> -
> -static const struct platform_device pipe3_phy_dev = {
> -       .name = "pipe3-phy",
> -       .id = -1,
> -       .dev = {
> -               .platform_data = {
> -                       .init_data = &init_data,
> -               },
> -       },
> -};
> -
> -then, while doing phy_create, the PHY driver should pass this init_data
> -       phy_create(dev, ops, pdata->init_data);
> -
> -and the controller driver (phy consumer) should pass the port name along with
> -the device to get a reference to the PHY
> -       phy_get(dev, "pcie");
> +8. PHY Mappings
> +
> +In order to get reference to a PHY without help from DeviceTree, the framework
> +offers lookups which can be compared to clkdev that allow clk structures to be
> +bound to devices. A lookup can be made statically by directly registering
> +phy_lookup structure which contains the name of the PHY device, the name of the
> +device which the PHY will be bind to and Connection ID string. Alternatively a
> +lookup can be made during runtime when a handle to the struct phy already
> +exists.
> +
> +The framework offers the following APIs for registering and unregistering the
> +lookups.
> +
> +void phy_register_lookup(struct phy_lookup *pl);
> +int phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id);
> +
> +void phy_unregister_lookup(struct phy_lookup *pl);
> +void phy_remove_lookup(struct phy *phy, const char *con_id, const char *dev_id);
>
>  9. DeviceTree Binding
>
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index ff5eec5..c8d0f66 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -26,6 +26,7 @@
>  static struct class *phy_class;
>  static DEFINE_MUTEX(phy_provider_mutex);
>  static LIST_HEAD(phy_provider_list);
> +static LIST_HEAD(phys);
>  static DEFINE_IDA(phy_ida);
>
>  static void devm_phy_release(struct device *dev, void *res)
> @@ -84,6 +85,138 @@ static struct phy *phy_lookup(struct device *device, const char *port)
>         return ERR_PTR(-ENODEV);
>  }
>
> +/**
> + * phy_register_lookup() - register PHY/device association
> + * @pl: association to register
> + */
> +void phy_register_lookup(struct phy_lookup *pl)
> +{
> +       mutex_lock(&phy_provider_mutex);
> +       list_add_tail(&pl->node, &phys);
> +       mutex_unlock(&phy_provider_mutex);
> +}
> +
> +/**
> + * phy_unregister_lookup() - remove PHY/device association
> + * @pl: association to be removed
> + */
> +void phy_unregister_lookup(struct phy_lookup *pl)
> +{
> +       mutex_lock(&phy_provider_mutex);
> +       list_del(&pl->node);
> +       mutex_unlock(&phy_provider_mutex);
> +}
> +
> +/**
> + * phy_create_lookup() - allocate and register PHY/device association
> + * @phy: the phy of the association
> + * @con_id: connection ID string on device
> + * @dev_id: the device of the association
> + *
> + * Creates and registers phy_lookup entry.
> + */
> +int phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id)
> +{
> +       struct phy_lookup *pl;
> +
> +       if (!phy || (!dev_id && !con_id))
> +               return -EINVAL;
> +
> +       pl = kzalloc(sizeof(*pl), GFP_KERNEL);
> +       if (!pl)
> +               return -ENOMEM;
> +
> +       pl->phy_name = dev_name(phy->dev.parent);
> +       pl->dev_id = dev_id;
> +       pl->con_id = con_id;
> +
> +       phy_register_lookup(pl);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(phy_create_lookup);
> +
> +/**
> + * phy_remove_lookup() - find and remove PHY/device association
> + * @phy: the phy of the association
> + * @con_id: connection ID string on device
> + * @dev_id: the device of the association
> + *
> + * Finds and unregisters phy_lookup entry that was created with
> + * phy_create_lookup().
> + */
> +void phy_remove_lookup(struct phy *phy, const char *con_id, const char *dev_id)
> +{
> +       struct phy_lookup *pl;
> +
> +       if (!phy || (!dev_id && !con_id))
> +               return;
> +
> +       list_for_each_entry(pl, &phys, node)
> +               if (!strcmp(pl->phy_name, dev_name(phy->dev.parent)) &&
> +                   !strcmp(pl->dev_id, dev_id) &&
> +                   !strcmp(pl->con_id, con_id)) {
> +                       phy_unregister_lookup(pl);
> +                       kfree(pl);
> +                       return;
> +               }
> +}
> +EXPORT_SYMBOL_GPL(phy_remove_lookup);
> +
> +static struct phy *phy_find(struct device *dev, const char *con_id)
> +{
> +       const char *dev_id = dev ? dev_name(dev) : NULL;
> +       int match, best_found = 0, best_possible = 0;
> +       struct phy *phy = ERR_PTR(-ENODEV);
> +       struct phy_lookup *p, *pl = NULL;
> +
> +       if (dev_id)
> +               best_possible += 2;
> +       if (con_id)
> +               best_possible += 1;
> +
> +       list_for_each_entry(p, &phys, node) {
> +               match = 0;
> +               if (p->dev_id) {
> +                       if (!dev_id || strcmp(p->dev_id, dev_id))
> +                               continue;
> +                       match += 2;
> +               }
> +               if (p->con_id) {
> +                       if (!con_id || strcmp(p->con_id, con_id))
> +                               continue;
> +                       match += 1;
> +               }
> +
> +               if (match > best_found) {
> +                       pl = p;
> +                       if (match != best_possible)
> +                               best_found = match;
> +                       else
> +                               break;
> +               }
> +       }
> +
> +       if (pl) {
> +               struct class_dev_iter iter;
> +               struct device *phy_dev;
> +
> +               class_dev_iter_init(&iter, phy_class, NULL, NULL);
> +               while ((phy_dev = class_dev_iter_next(&iter))) {

We have the case with phy-exynos5-usbdrd driver, which registers two
phys usb2-phy and usb3-phy
both being used by xhci (after dwc3 creates a lookup table).

The phy_dev is coming same for both the PHYs, and that's the reason
when i try to get
"usb2-phy" and "usb3-phy" i end up getting only usb2-phy.
This is happening with V4 of this patch; V3 seems fine. The only
differnece i see is
we are creating the phy_lookup_table using phy_dev->parent.

Is there something that i am missing ?

> +                       if (!strcmp(dev_name(phy_dev->parent), pl->phy_name)) {
> +                               phy = to_phy(phy_dev);
> +                               break;
> +                       }
> +               }
> +               class_dev_iter_exit(&iter);
> +       }
> +
> +       /* fall-back to the old lookup method for now */
> +       if (IS_ERR(phy))
> +               phy = phy_lookup(dev, con_id);
> +       return phy;
> +}
> +
>  static struct phy_provider *of_phy_provider_lookup(struct device_node *node)
>  {
>         struct phy_provider *phy_provider;
> @@ -463,7 +596,7 @@ struct phy *phy_get(struct device *dev, const char *string)
>                         string);
>                 phy = _of_phy_get(dev->of_node, index);
>         } else {
> -               phy = phy_lookup(dev, string);
> +               phy = phy_find(dev, string);
>         }
>         if (IS_ERR(phy))
>                 return phy;
> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
> index 9fda683..2696b95 100644
> --- a/include/linux/phy/phy.h
> +++ b/include/linux/phy/phy.h
> @@ -110,6 +110,20 @@ struct phy_init_data {
>         .port           = _port,                                \
>  }
>
> +struct phy_lookup {
> +       struct list_head node;
> +       const char *phy_name;
> +       const char *dev_id;
> +       const char *con_id;
> +};
> +
> +#define PHY_LOOKUP(a, b, c)    \
> +       {                               \
> +               .phy_name = a,          \
> +               .dev_id = b,            \
> +               .con_id = c,            \
> +       }
> +
>  #define        to_phy(a)       (container_of((a), struct phy, dev))
>
>  #define        of_phy_provider_register(dev, xlate)    \
> @@ -174,6 +188,10 @@ struct phy_provider *__devm_of_phy_provider_register(struct device *dev,
>  void of_phy_provider_unregister(struct phy_provider *phy_provider);
>  void devm_of_phy_provider_unregister(struct device *dev,
>         struct phy_provider *phy_provider);
> +void phy_register_lookup(struct phy_lookup *pl);
> +void phy_unregister_lookup(struct phy_lookup *pl);
> +int phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id);
> +void phy_remove_lookup(struct phy *phy, const char *con_id, const char *dev_id);
>  #else
>  static inline int phy_pm_runtime_get(struct phy *phy)
>  {
> @@ -345,6 +363,15 @@ static inline void devm_of_phy_provider_unregister(struct device *dev,
>         struct phy_provider *phy_provider)
>  {
>  }
> +static inline void phy_register_lookup(struct phy_lookup *pl) { }
> +static inline void phy_unregister_lookup(struct phy_lookup *pl) { }
> +static inline int
> +phy_create_lookup(struct phy *phy, const char *con_id, const char *dev_id)
> +{
> +       return 0;
> +}
> +static inline void phy_remove_lookup(struct phy *phy, const char *con_id,
> +                                    const char *dev_id) { }
>  #endif
>
>  #endif /* __DRIVERS_PHY_H */
> --
> 2.1.1
>
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-- 
Best Regards
Vivek Gautam
Samsung R&D Institute, Bangalore
India
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